Mongomapper嵌入文档“无法序列化对象”错误

Question

我对 mongodb 很陌生，我正在使用 sinatra 和 mongomapper 通过以下设置更新嵌入文档的值：

class TeamMember
  include MongoMapper::Document

  key :name, String, :required => true

  many :team_member_projects
end

class TeamMemberProject
  include MongoMapper::EmbeddedDocument

  key :date, Date, :required => true

  one :project 
end

class Project
  include MongoMapper::Document

  key :name, String, :required => true
end

修饰符代码是：

team_member = TeamMember.find(params[:team_member])
project = Project.find(params[:project])
date = Date.parse(params[:date])

tm_project = TeamMemberProject.new(:project => project, :date => date)
team_member.push(:team_member_projects => tm_project)
team_member.save

但我收到 .push 行的错误：

BSON::InvalidDocument at /project/add
Cannot serialize an object of class TeamMemberProject into BSON.

我没有正确声明我的嵌入文档吗？或者还有其他方法来更新嵌入文档，我不知道。我正在尝试使用： http://mongomapper.com/documentation/plugins/modifiers。 html#push

Answer 1

这似乎有效

team_member = TeamMember.find(params[:team_member])
project = Project.find(params[:project])
date = Date.parse(params[:date])

tm_project = TeamMemberProject.new(:project_id => project.id, :date => date)
team_member.team_member_projects << tm_project
team_member.save

似乎我必须使用 project.id 。不知道为什么。也不知道为什么我的 .push 不起作用，因为我认为它与 << 做同样的事情。